Hi Hans,

Thanks for the quick fix.
Indeed the spurious character does not show up anymore, but in the minimal example below the default body font seems to be set to bold italic, please see the attached PDF (I did not observe this in my real documents, but curiously it shows up in this minimal example): it may be that I am using a wrong font definition here. 
The version of ConTeXt is  2016.11.18 22:20 MKIV beta  fmt: 2016.11.18.

%%%% begin bug-beta.tex
\definefallbackfamily[mainface][serif][palatino]
\definefontfamily[mainface][sans][palatino] 
\setupbodyfont[mainface]

\starttext

Why is the text in bold italic?

\stoptext
%%%% end bug-beta.tex

Best regards: OK